Today’s porn is not your father’s Playboy. Type porn into Google and you won’t see anything that looks like the old pinups; instead, you will be catapulted into a world of sexual cruelty and brutality where women are subject to body-punishing sex and called vile names. It’s not surprising how little women really know about porn today, since most women avoid looking at these sites. Not true for the men I meet, especially the college-age and even high-school boys. They have grown up with porn and, for them, this has been their major form of sex education.

In porn, sex is not about making love. The feelings and emotions we normally associate with such an act — connection, empathy, tenderness, caring, affection — are missing, and in their place are those we normally associate with hate — fear, disgust, anger, loathing and contempt. In porn, the man “makes hate” to the woman, as each sex act is designed to deliver the maximum amount of degradation. Whether it be choking her or violent intercourse, the goal of porn sex is to illustrate how much power he has over her. Yet the women are still portrayed as enjoying these scenes. It is images like these that are now commonplace all over the Internet and are shaping the way men think about sex, relationships and intimacy.

The size of the industry today is staggering. Though reliable numbers are hard to find, the global industry has been estimated to be worth around $96 billion in 2006, with the US market worth approximately $13 billion. Each year, more than 13,000 films are released, and despite their modest budgets, pornography revenues rival those of all the major Hollywood studio films combined. According to Internet Filter Reviews, there are 420 million Internet porn pages, 4.2 million porn websites, and 68 million daily porn search engine requests. A recent study from Optenet, an online security firm, found that approximately 37% of online pages contain pornographic content. Meanwhile, the number of porn sites increased 17% from last year.

Without a doubt, a key factor driving the growth of the porn market has been the development of technologies allowing users to buy and consume porn in private, without embarrassing trips to seedy stores or video rental shops. These technologies also enable pornography to be viewed anywhere, anytime; even the global cellphone market for porn is expected to reach $3.5 billion this year, according to the Britain-based Juniper Research.

This is a business with considerable political clout, with the capacity to lobby politicians, engage in expensive legal battles, and use public relations to influence public debate. Like the tobacco industry, this is not a simple matter of consumer choice; rather the business is increasingly able to deploy a sophisticated and well-resourced marketing machine, not just to push its wares but also to cast the industry’s image in a positive light. Indeed, one of the key myths that the industry promotes is that porn is harmless fun: that it is all about fantasy and play, and that we should not take it too seriously.

My interviews with college-age men tell a very different story. When I talk to men about their experiences with porn, it is clear that not all are affected in the same way, but affected they are. Remember, this is the generation that grew up with Internet porn, and some studies put the first age of viewing porn at 11 years. Unlike previous generations, these boys and men have an unlimited supply of hardcore porn 24 hours a day.

Many of the men I talk to believe that porn sex is what women want, and they become upset and angry when their sex partner, perhaps their wife, girlfriend or a one night hook-up, refuses to look or behave like their favorite porn star. The women often refuse to perform the sex acts the men have routinely enjoyed watching, and next to the screaming orgasms and sexual gymnastics of porn sex, real sex with real women starts to feel boring and bland.

One student told me that “I love porn and I try out the sex on my girlfriend, but she isn’t interested. I dumped the last girl I was with because she wanted to keep the sex straight. That’s not for me. If women don’t want to try different things, then I am not interested.”

These men have become so accustomed to porn sex that some are disappointed by their own sexual performance. When they compare themselves to Viagra-fortified actors, the guys I talk to often admit to feeling like sexual losers and worry that something is wrong with them. Adam grew up watching his father’s porn and felt that “porn taught me all I know about sex. My parents never mentioned the word sex at home, and sex ed in school was a . . . joke. I had this image of how great sex would be, both of us going at it for hours. So it was kind of a shock the way the real thing turned out . . .”

What troubles many of these men most is that they need to pull up the porn images in their head in order to be satisfied with their partner. They replay porn scenes in their minds, or think about having sex with their favorite porn star when they are with their partners. Dan was concerned about his sexual performance with women. He told me that “I am not really focusing on the girl but on the last scene I watched.” I asked him if he thought porn had in any way affected his sexuality. He said, “I don’t know. I started looking at porn before I had sex, so porn is pretty much how I learned about sex. It can be a kind of problem to think about porn as much as I do, especially when I’m with my girlfriend. It means I’m not really present with her. My head is somewhere else.”

Porn has become so violent and degrading that we ignore it at our peril. We are now bringing up a generation of boys on cruel, violent porn and given that images shape the way people think and behave, this is going to have a profound effect on their sexuality and on the culture as a whole. Porn use is one of the major public health issues of our time and one that needs to be tackled now before we bring up a new generation of boys on even harder images.

Unfortunately, there are no easy answers. Parents face a daunting technical challenge to keep porn from their children. With education and growing awareness, we can only hope that eventually society will rebel, to make it socially unacceptable for there to be such easy access to porn, for men to spend so much time looking at it, for our ideas about sexuality to be so warped.

Gail Dines is the author of “Pornland: How Porn Has Hijacked Our Sexuality” (Beacon Press), out this week.